| SHORT COMMUNICATION
|Year : 1997 | Volume
| Issue : 2 | Page : 125-128
Nitric oxide modulation of cardiovascular responses from ventral surface of medulla in cat
S Verma, R Raghubir, GK Patnaik
Objectives: To analyse the functional significance of Nitric oxide (NO) in cardiovascular regulation from rostral ventral medulla in cats using nitric oxide precursor, donor and guanylate cyclase inhibitor, methylene blue.
Methods: Arterial pressure was recorded from femoral artery of chloralose anaesthetized cats through statham P23 DC transducer on Grass model P7 polygraph and the heart rate was also triggered using Grass 7P4 tac hograph. The effect on blood pressure and heart rate was monitored following topical application of NO precursor, L-Arg (1,2 and 5% for 10 minutes), NO donor, sodium nitroprusside (SNP) (0.1 and 0.5% for 10 minutes) and methylene blue (MB) (1% for 10 minutes) on exposed rostro-ventral medulla.
Results: L-Arginine (1,2 and 5%) did not produce significant effects on blood pressure and heart rate. However, topical application of SNP ( O.1%-0.5%) produced significant hypotension and bradycardia which was attenuated by guanylate cyclase inhibitor methylene blue.
Conclusion:The significant hypotension and bradycardia produced by SNP and blockade by methylene blue suggests the possible involvement of NO-cGMP mechanism in central cardiovascular regulation.
Source of Support: None, Conflict of Interest: None